Preparation method of sour dough steamed bun based on liquid fermentation method

Abstract

The preparation method of the sour dough steamed bun based on the liquid state fermentation method comprises the following steps: 1) mixing liquid state acid, water and wheat flour to prepare medium-sized flour paste, and fermenting the medium-sized flour paste at normal temperature; (2) mixing the sponge paste prepared in the step (1) with wheat flour and alkali to prepare main dough; and (3) cutting, tabletting, forming, fermenting and steaming the main dough prepared in the step (2) to obtain the sour dough steamed bun. Industrial production of the sour dough steamed bun is facilitated, and the taste and flavor of the sour dough steamed bun are further improved.

Description

Technical Field

[0001] The invention relates to the technical field of food processing, in particular to a method for preparing sour dough steamed bread based on a liquid fermentation method. Background Art

[0002] With the development and promotion of yeast, it has not only brought great convenience to the production of flour products, but also promoted the industrial production of steamed bread. At present, it has been widely used in the industrial production of steamed bread. However, although yeast has the advantages of strong fermentation ability and fast fermentation speed, its cost is too high. Compared with mixed fermentation starters such as old dough, leavener, and sour dough, the steamed bread produced by it has poor taste and poor anti-aging.

[0003] In recent years, steamed bread made with traditional fermentation agents has become more and more popular due to its unique taste. However, the traditional fermentation method is solid-state fermentation, which has problems such as large floor space and low production efficiency. In addition, the taste and flavor of steamed bread produced by traditional solid-state fermentation still need to be further improved. Summary of the invention

[0004] The present invention aims to provide a method for preparing sour dough steamed bread based on a liquid fermentation method, so as to facilitate the industrial production of sour dough steamed bread and further improve its taste and flavor.

[0005] In order to solve the above technical problems, the specific scheme adopted by the present invention is: a method for preparing sour dough steamed bread based on liquid fermentation method, comprising the following steps:

[0006] 1) Mixing liquid acid seed, water and wheat flour to prepare a medium seed batter, and fermenting the medium seed batter at room temperature;

[0007] 2) Mixing the intermediate batter prepared in step 1) with wheat flour and alkali to prepare a main dough;

[0008] 3) The main dough prepared in step 2) is divided, sheeted, formed, proofed and steamed to obtain sour dough steamed bread.

[0009] Preferably, in step 1), the liquid acid contains yeast and lactic acid bacteria, and the number of live yeast cells is 5.14×10 7 ~6.72×10 7 CFU / g; the number of viable lactic acid bacteria is 5.34×10 8 ~8.33×10 8 CFU / g.

[0010] Preferably, in step 1), the added mass of liquid sourdough seed accounts for 30-50% of the total added mass of wheat flour in the sourdough steamed bread.

[0011] Preferably, the added mass of wheat flour in step 1) accounts for 20-40% of the total added mass of wheat flour in the sour dough steamed bread, and the added mass of wheat flour in step 2) accounts for 60-80% of the total added mass of wheat flour in the sour dough steamed bread.

[0012] Preferably, the preparation method of the liquid acid seed in step 1) is: mixing the solid acid seed, wheat flour and water in a ratio of 3: (2.9-3.1): (3.9-4.1).

[0013] Preferably, the prepared liquid acid seed is expanded to meet production needs, and the expansion method is: the prepared acid seed, wheat flour and water are mixed in a ratio of 1: (0.9-1.1): (0.9-1.1).

[0014] Preferably, the room temperature fermentation temperature in step 1) is 23-27° C., and the fermentation time is 3-9 hours.

[0015] Preferably, the added mass of the alkali in step 2) is calculated according to the following formula:

[0016] m(g)=5.3×10 -4 M Δ V,

[0017] Wherein, m is the amount of alkali added, in g; M is the mass of the middle batter, in g; Δ V is the volume of sodium hydroxide solution consumed when 10 g of the medium batter is mixed with 90 mL of distilled water using a pulp beater to prepare a suspension, and then the pH is titrated to 8.5 using 0.1 mol / L sodium hydroxide solution, in mL.

[0018] Preferably, the proofing time in step 3) is 40-80 min, the proofing temperature is 35-40° C., and the proofing relative humidity is 75-85%.

[0019] Preferably, the number of times of pressing the dough in step 3) is 7-9 times. Beneficial Effects

[0020] Before preparing the main dough, the present invention first mixes liquid yeast, part of wheat flour and all of water to prepare a medium batter, and the medium batter has good fluidity and can be transported by pipeline, so that the production area occupied can be greatly reduced by pipeline transportation and the production efficiency can be greatly improved.

[0021] The leavening agent used in the present invention is a liquid acid seed prepared from a solid acid seed, which belongs to a mixed bacteria system and retains the advantages of high metabolic activity of type I acid dough and liquid fluidity of type II acid dough. The steamed bread made with the liquid acid seed has good flavor and taste, and the strain has strong metabolic activity. When making steamed bread, little or no yeast is added, which greatly reduces the production cost and greatly improves the product quality. In addition, the liquid acid seed only needs to be mixed with water and wheat flour in a specific ratio to complete the expansion to meet the needs of industrial production. In the above-mentioned preparation and expansion process, no sterile environment is required, the original mixed bacteria system is not destroyed, and continuous culture can be performed at will, which makes it easier to manage and reproduce during the production process.

[0022] In addition, since the above-mentioned liquid acid seed is a mixed bacterial system, there are multiple dominant bacterial species, and the number of yeast and lactic acid bacteria has reached the fermentation level. In a liquid environment, yeast metabolism is high, and moderate acidity can promote yeast growth and gas production. In an acidic environment, it can inhibit the activity of other competitive microorganisms, thereby reducing the competition of these microorganisms on yeast and indirectly promoting the fermentation effect of yeast. The addition of liquid acid seed can effectively control the fermentation rate to avoid too fast fermentation, which makes the product flavor bland and the structure unstable.

[0023] In a preferred embodiment of the present invention, wheat flour is added to the middle batter and the main dough in a specific ratio. Under this ratio, the fermentation performance of the middle batter is better and has good fermentation activity, so that the steamed buns produced have a larger specific volume, better taste, and higher sensory score. DETAILED DESCRIPTION

[0024] A method for preparing sour dough steamed bread based on a liquid fermentation method of the present invention comprises the following steps:

[0025] 1) Mix liquid sourdough, wheat flour and all the water required for preparing sourdough steamed bread, and ferment the prepared medium-seed batter at room temperature of 23-27°C for 5-9 hours; the amount of wheat flour used in the medium-seed batter accounts for 20%-40% of the total amount of wheat flour used in sourdough steamed bread by weight; the amount of liquid sourdough accounts for 30%-50% of the total amount of wheat flour used in sourdough steamed bread by weight. The wheat flour used in the preparation of sourdough steamed bread is high-grade snowflake flour produced by Hebei Dark Horse Wheat Flour Co., Ltd.

[0026] The source of the above-mentioned liquid acid seed is obtained by screening and continuous cultivation in the laboratory of the applicant. The method for preparing the liquid acid seed is: the solid acid seed that has been continuously cultivated is mixed with fresh wheat flour and water in a ratio of 3:3:4 to form a liquid acid seed. In order to meet the needs of industrial production, the method for further expanding the liquid acid seed is: the liquid acid seed that has been continuously cultivated is mixed with fresh wheat flour and water in a ratio of 1:1:1, and then placed at room temperature for cultivation for a period of time (12 to 24 hours) to obtain the liquid acid seed after expanded cultivation; it can be continuously expanded as needed until the requirements for the amount of acid seed used in the medium batter are met. The microbial content of the mature acid seed after expansion is that the number of live yeasts in the acid seed is 5.14×107~6.72×107CFU / g; the number of live lactic acid bacteria is 5.34×108~8.33×108CFU / g.

[0027] 2) After the fermented medium dough in step 1) is left to stand at room temperature, it is mixed with the remaining wheat flour and alkali to form the main dough. The mass percentage of wheat flour used in this step to the total mass of wheat flour used in sour dough steamed bread is 60% to 80%. The mass of alkali added is calculated according to the following formula:

[0028] m(g)=5.3×10 -4 M Δ V,

[0029] Wherein, m is the amount of alkali added, in g; M is the mass of the middle seed batter, in g; ΔV is the volume of sodium hydroxide solution consumed when 10 g of the middle seed batter is mixed with 90 mL of distilled water using a beater to make a suspension, and then the pH is titrated to 8.5 with 0.1 mol / L sodium hydroxide solution, in mL.

[0030] 3) The main dough prepared in step 2) is divided, sheeted, formed, proofed and steamed to obtain sour dough steamed buns. The number of times of pressing the dough is preferably 7 to 9 times. The method of pressing the dough is not particularly limited, and a pressing method known to those skilled in the art can be used. The purpose of pressing the dough is (1) to exhaust air so that the texture of the steamed bun is more uniform; (2) to improve the dough structure; (3) to adjust the shape; and (4) to reduce surface cracks. After the steamed bun blank is obtained, the steamed bun blank is proofed. The role of proofing: the dough is fully expanded and fermented, and the yeast in the dough will produce carbon dioxide gas, causing the dough to expand, making the steamed bun more fluffy and light when steamed. The proofing time is preferably 50 to 70 minutes, and more preferably 60 minutes; the proofing temperature is preferably 37 to 39°C, and more preferably 38°C; the relative humidity of proofing is preferably 80% to 85%, and more preferably 83%. In the embodiment of the present invention, proofing is carried out in a proofing box. The present invention has no particular limitation on the specific model of the proofing box, and a proofing box known to those skilled in the art can be used. The proofing box in the embodiment of the present invention is purchased from Huizhou Gaobi Baking Equipment Co., Ltd. After the steamed bun blank is proofed, the present invention steams the proofed steamed bun blank to obtain sour dough steamed buns. In the present invention, the steaming temperature is preferably 95-105°C, more preferably 100°C. The steaming time is 18-22min, more preferably 20min. After steaming, the sour dough steamed buns are cooled for 1h and various indicators are observed and measured. The indicators include the specific volume, texture and sensory evaluation of the steamed buns. There is no special limitation on the measuring method, and the measuring method well known to those skilled in the art can be used.

[0031] Below, the liquid acid seed expansion time (h) D, the amount of wheat flour added in the middle seed batter (%) A, the room temperature fermentation time (h) C and the amount of liquid acid seed added (%) B were selected as the test factors, and the sensory score of steamed bread was used as the response value to conduct a four-factor three-level response surface test. Among them, the mass percentage of the liquid acid seed used in the total amount of wheat flour used in sour dough steamed bread was set to 30%, 40% and 50% respectively; the expansion time of the liquid acid seed at room temperature (25°C) was 12h, 15h and 18h; the room temperature fermentation time of the middle seed batter was set to 5h, 7h and 9h respectively; the mass percentage of the wheat flour used in the middle seed batter to the total amount of wheat flour used in sour dough steamed bread was set to 20%, 30% and 40% respectively. The total amount of wheat flour used when making a single batch of sour dough steamed bread is 1000g. The factors and levels of the response surface test are shown in Table 1. Table 1 Response surface factor level table

[0032] Then, the quality of the prepared sour dough steamed bread was evaluated, including specific volume, texture and sensory evaluation. The quality evaluation method referred to the method of Liu Changhong and GB / T35991-2018 to measure the height, width, height-to-diameter ratio, specific volume and texture of the steamed bread. The evaluation criteria are shown in Table 2. Table 2 Sensory evaluation of liquid sour dough steamed bread

[0033] The sensory evaluation of the sour dough steamed bread prepared in Examples 1 to 29 is shown in Tables 3 and 4 Table 3 Sensory scoring data of each embodiment Table 4 Analysis of variance of response surface quadratic model

[0034] As shown in Table 4, F = 23.88488, p < 0.0001, the regression model is extremely significant, and the lack of fit term is not significant (P = 0.0504). The fitting coefficient R 2 =0.9598, correction fitting coefficient R 2 ad j =0.9196, indicating that the model has good fitting degree, small error, and reliability, and is suitable for the optimization of the fermentation process of liquid fermented sour dough steamed bread. Table 3 shows that the fermentation process has a significant impact on the sensory score of steamed bread: the amount of acid added > fermentation time > expansion time > wheat flour added. The amount of acid added and fermentation time have a significant impact on the sensory score of steamed bread.

[0035] Determination and verification test of the optimal process:

[0036] The optimal fermentation process of liquid fermented sour dough steamed bread was obtained by simulation fitting: the addition of wheat flour was 30.43%, the addition of acid seed was 41.37%, the fermentation time was 6.78h, and the expansion time was 14.88h. The sensory score of steamed bread was 91.1855 points. Considering the feasibility of actual production and verifying the accuracy of the results of response surface optimization method, the process of liquid fermented sour dough steamed bread was adjusted to 30% wheat flour addition, 40% acid seed addition, 7h fermentation time, and 15h expansion time. After actual experiments, the sensory score of steamed bread was 91.68 points, which was not much different from the predicted results. Therefore, the response surface experimental design is reasonable.

[0037] Finally, the distribution ratio of the middle batter flour and the main dough flour for the specific volume and sensory evaluation of the sour dough steamed bread products is shown in Table 5 below. Table 5 shows that in the most preferred embodiment of the present invention, when the middle batter flour and the main dough flour are distributed in a ratio of 3:7, the fermentation performance of the middle batter is better, the steamed bread produced with good fermentation activity has a large specific volume and a high sensory score. This shows that under the preparation conditions of the appropriate amount of wheat flour added in the middle stage, the gluten network has been initially formed, which contributes to the elasticity and structure of the final steamed bread, making the steamed bread produced have a good flavor. However, when the amount of wheat flour added in the middle batter is small, the fermentation activity is insufficient, the steamed bread is small in size, the structure is tight, the hardness is large, and the flavor is poor; when the amount of wheat flour added in the middle batter is too much, the gas production of the main dough decreases, the structure of the steamed bread is fragile, and the taste is rough. Table 5 Effect of wheat flour addition in batter on steamed bread

[0038] Based on the specific distribution ratio, the middle-seed batter prepared by the present invention has better fluidity, can have a better fermentation speed and fermentation effect, and the final product has a good internal structure, the steamed bun has a larger specific volume, and has a good taste and flavor.

Claims

1. A method for preparing sour dough steamed bread based on liquid fermentation method, characterized in that: The following steps are involved: 1) Mixing liquid acid seed, water and wheat flour to prepare a medium seed batter, and fermenting the medium seed batter at room temperature; 2) Mixing the intermediate batter prepared in step 1) with wheat flour and alkali to prepare a main dough; 3) The main dough prepared in step 2) is divided, sheeted, formed, proofed and steamed to obtain sour dough steamed bread.

2. The method for preparing sour dough steamed bread based on liquid fermentation method according to claim 1, characterized in that: In step 1), the liquid acid seed contains yeast and lactic acid bacteria, and the number of live yeast cells is 5.14×10 7 ~6.72×10 7 CFU / g; the number of viable lactic acid bacteria is 5.34×10 8 ~8.33×10 8 CFU / g.

3. The method for preparing sour dough steamed bread based on liquid fermentation method according to claim 1, characterized in that: In step 1), the added mass of liquid sourdough seed accounts for 30-50% of the total added mass of wheat flour in the sourdough steamed bread.

4. The method for preparing sour dough steamed bread based on liquid fermentation method according to claim 1, characterized in that: The added mass of wheat flour in step 1) accounts for 20-40% of the total added mass of wheat flour in sour dough steamed bread, and the added mass of wheat flour in step 2) accounts for 60-80% of the total added mass of wheat flour in sour dough steamed bread.

5. The method for preparing sour dough steamed bread based on liquid fermentation method according to claim 1, characterized in that: The preparation method of the liquid acid seed in step 1) is: mixing the solid acid seed, wheat flour and water in a ratio of 3: (2.9-3.1): (3.9-4.1).

6. The method for preparing sour dough steamed bread based on liquid fermentation method according to claim 5, characterized in that: The prepared liquid acid seed is expanded to meet production needs, and the expansion method is: the prepared acid seed, wheat flour and water are mixed in a ratio of 1: (0.9-1.1): (0.9-1.1).

7. The method for preparing sour dough steamed bread based on liquid fermentation method according to claim 1, characterized in that: The room temperature fermentation temperature in step 1) is 23-27° C., and the fermentation time is 3-9 hours.

8. The method for preparing sour dough steamed bread based on liquid fermentation method according to claim 1, characterized in that: The added mass of the alkali in step 2) is calculated according to the following formula: m(g)=5.3×10 -4 MΔV, Wherein, m is the amount of alkali added, in g; M is the mass of the middle batter, in g; Δ V is the volume of sodium hydroxide solution consumed when 10 g of the medium batter is mixed with 90 mL of distilled water using a pulp beater to prepare a suspension, and then the pH is titrated to 8.5 using 0.1 mol / L sodium hydroxide solution, in mL.

9. The method for preparing sour dough steamed bread based on liquid fermentation method according to claim 1, characterized in that: The proofing time in step 3) is 40-80 minutes, the proofing temperature is 35-40° C., and the proofing relative humidity is 75-85%.

10. The method for preparing sour dough steamed bread based on liquid fermentation method according to claim 1, characterized in that: In step 3), the number of times of pressing the dough is 7-9 times.

Images